Shark Tooth From Andalusia, Alabama

[cowsharks]

A friend of mine hunts various streams in or near Andalusia, Alabama and finds tons of shark and ray material. One tooth type however puzzles him regarding a proper ID. The pic below is one example of this shark tooth that he isn't sure if it is an Otodus obliquus or type of Cretalamna. The formation that he finds these teeth in is Eocene, but beyond that I'm not sure of the exact layer name. This particular tooth type isn't rare or anything, he just isn't sure what species it belongs to.

Any ideas? Thanks.

[Al Dente]

A couple of guesses, C. twiggsensis and S. koerti both can have similar side cusps and are Eocene.

[Harry Pristis]

This is from Parmley and Cicimurri in their 2003 paper. I don't have full faith in this revision, but it tells the tale of how complicated this taxonomy can become:

Late Eocene sharks of the Hardie Mine local fauna of Wilkinson County, Georgia.

Carcharias sp. aff. C. koerti (Stromer 1910)

Eocene teeth of the type described above have variously been referred to Lamna (18), Cretolamna (20) and Serratolamna (9). Though the crown morphology is similar, the Hardie Mine l.f. teeth can be distinguished from Cretolamna by the consistent presence of a weak nutritive groove, which is usually absent in Cretoxyrhinidae (8). A lingual nutritive groove is found on teeth of Serratolamna (29), which can also have up to three pairs of lateral cusplets (30). The teeth in our sample generally have one large pair of lateral cusplets and, if present, a second smaller pair. For these reasons we exclude this tooth type from Cretolamna and Serratolamna, and place it within Carcharias, retaining the species epithet koerti, which is a taxon originally described by Stromer (31) from the Eocene of Africa.

[costagrayi]

The formation below the Point-A dam is described as being upper-middle Eocene. Tallahata Formation - Lisbon Formation if this helps.

[shark57]

Daryl, this tooth is a dead ringer for the Cretalamna teeth we find at the "Muddy Creek" site (Eocene) and Liverpool Point on the Potomac (Paleocene). To me it doesn't resemble a koerti at all. The Cretalamna are always short and stocky, rarely exceed one inch, and usually have that second pair of very small cusplets attached to the first. The crown and cusplets are also very thick for the size. Small Otodus very rarely have a second set of cusplets.

Edited July 8, 2014 by shark57

[Sélacien34]

I agree that this tooth doesn't look to C. koerti. The shape of the root and crown looks like Cretalamna, Otodus obliquus can have secondary cusplets at the Eocene, but does this tooth is really from Eocene ? Could it be an early Otodus ?

http://users.skynet.be/somniosus/Palaeocene_Otodus%20&%20Cretalamna.htm

http://www.fossilmall.com/PaleoRelic/edfossils/fcfish/FCFF02.jpg

[FossilDAWG]

A couple of guesses, C. twiggsensis and S. koerti both can have similar side cusps and are Eocene.

C. twiggsensis is considered to be a junior synonym of S. koerti by several recent authors. For example, on Elasmo we find:

"Case (1981:58-59) erected Lamna twiggsensis for a tooth-design from the Eocene of Georgia; these teeth are identical to Serratolamna koerti and can only be viewed as a junior synonym of the latter."

Another example is Parmley and Cicimurri (2003) as mentioned above by Harry.

The proper generic assignment of these teeth seems problematic to me. Parmley and Cicimurri at least explain their logic behind excluding Serratolamna and Cretalamna and favoring Carcharias. No doubt confusion arises because the various genera grade into one another over geological time, and teeth from the same shark can be very different depending on position in the mouth. It's worth remembering that our various "genera" are artificial entities, constructed by humans so that we can rationally discuss the various species, and the boundaries between genera are sometimes defined by accidents of history (who published what name when) rather than real biological discontinuities.

With regard to the original post, it's worth considering that the Andalusia (Point A Dam) site is thought to be a lag deposit at the base of the Lisbon, where it rests on the Tallahata (although Case calls the whole outcrop Tallahata). Both formations are Middle Eocene. The Hardie Mine site discussed in Parmley & Cicimurra (2003) is Clinchfield Formation, of very latest Eocene age, and so several million years younger than the Andalusia outcrop.

Don

Edited July 8, 2014 by FossilDAWG

[cowsharks]

Daryl, this tooth is a dead ringer for the Cretalamna teeth we find at the "Muddy Creek" site (Eocene) and Liverpool Point on the Potomac (Paleocene). To me it doesn't resemble a koerti at all. The Cretalamna are always short and stocky, rarely exceed one inch, and usually have that second pair of very small cusplets attached to the first. The crown and cusplets are also very thick for the size. Small Otodus very rarely have a second set of cusplets.

I agree and originally told my friend (without much hesitation) that this tooth was a Cretalamna. He replied with the comment that he was told by another collector from Andalusia that Cretalamna "aren't supposed to be in that formation"; this was information passed 2nd hand through a "Paleontologist" who was familiar with the fauna from the location where they were being found.

To me the tooth sure looks more like a Cretalamna than Koerti. I've asked my friend if he can come up with several more examples of this tooth type to see if any more diagnostic characteristics can be determined.

Appreciate all the comments and resources folks have replied with. It's all great information.

Are there any publications specifically done on the Eocene of Alabama?

thanks,

Daryl.

[FossilDAWG]

Here is a link to a MSc thesis on the Point A Dam site. There are photos of the elasmobranch teeth found during the study in an appendix at the end. The names associated with those photos are in the "Systematic Paleontology Table" on pages 34-38, which is a confusing arrangement but there you go. The tooth design in the OP of this thread seems to match what they are calling Brachycarcharias lerichei in the thesis.

Don

[MarcoSr]

Daryl

I was originally thinking Brachycarcharias lerichei like Don pointed out from the Point A Dam site because of the similarity to teeth from "Muddy Creek". However I can also see the similarity to C. twiggsensis and S. koerti that Eric pointed out. Other similar specimens and more pictures would definitely help. Plus if you could take another picture of this specimen. I can't tell if the specimen you posted has a shallow nutrient grove or not from the picture. That would be an important feature. I just don't remember seeing the additional reduced side cusplet like this specimen has on any of my Cretolamna from Liverpool Point or Muddy Creek. I will check them. However the Brachycarcharias from those sites do have the additional reduced side cusplet on some file positions.

Marco Sr.

[Sélacien34]

Illuminating the picture that doesn't helped much, looks like a foramen on the lingual protuberance of the root like Cretalamna or Otodus, but no nutrient groove unlike to B. lerichei (or C. koerti), which have high right and thinner lateral cusplets than these wide triangular cusps. The shape of the root evokes Cretalamna too.

Edited July 8, 2014 by Sélacien34

[Auspex]

Illuminating the picture that doesn't helped much, looks like a foramen on the lingual protuberance of the root like Cretalamna or Otodus, but no nutrient groove unlike to B; lerichei (or C. koerti), which have lateral cusplets high right and thinner than these wide triangular cusps. The shape of the root evokes Cretalamna too.

post-2077-0-72097500-1404765498.jpgBrachycarcharias lerichei-Serratolamna lerichei-Lamna lerichei-Carcharias vincenti , Ypresian.jpg

Excellent observations. Foramen vs. groove is compelling.

[Harry Pristis]

FossilDAWG Posted Today, 10:11 AM

Here is a link to a MSc thesis on the Point A Dam site. There are photos of the elasmobranch teeth found during the study in an appendix at the end. The names associated with those photos are in the "Systematic Paleontology Table" on pages 34-38, which is a confusing arrangement but there you go. The tooth design in the OP of this thread seems to match what they are calling Brachycarcharias lerichei in the thesis. Don

Thanks for posting the link to the MSc thesis, Don . . . that is interesting. But, the thesis is primarily a sedimentology/stratigraphy study, not a taxonomic study of the fauna. The author provides the sources of her identifications:

The samples were separated according to taxonomic rank using literature

found in A Pictorial Guide to Fossils (Case, 1992), Handbook of Paleoichthyology

Chondrichthyes II, FAO Species Catalogue (Compagno, 1994), The Shark Almanac

(Allen, 1999) and Handbook of Paleoichthylolgy; Chondrichthyes II Mesozoic and

Cenozoic (Cappetta, 1987).

My guess is that she had to choose to follow one author or another in naming the tooth Brachycarcharias lerichei.

Bretton Kent (1994) speaks of mackerel shark fossils from the Chesapeake Bay area, specifically

those in the genera Cretodus, Cretolamna, Serratolamna, Otodus, Isurolamna and Carcharoides. Kent says:

The validity of some of these genera is uncertain, since the boundaries between them are frequently not clearly defined.

Sometimes (particularly in this cluster of genera and species) it's just fruitless to try to identify a single tooth.

Edited July 9, 2014 by Harry Pristis

[Al Dente]

C. twiggsensis is considered to be a junior synonym of S. koerti by several recent authors.

There seems to be a lot of disagreement about where to place twiggsensis and koerti. Cappetta's recent update of Chondrichthyes volume 3e (2012) still has twiggsensis under Cretolamna and koerti he has under Carcharias but makes the statement that it belongs somewhere else. A recent paper by Underwood, Ward and others "Shark and ray faunas in the Middle and Late Eocene of the Fayum Area, Egypt" (2010) places both koerti and twiggsensis under Brachycarcharias but as distinct species occurring together. Another recent paper that I need to search for has both occurring in Western Sahara in the Middle and Late Eocene as separate species.

[MarcoSr]

The experts can't even agree on the spelling of Cretolamna/Cretalamna. Cappetta spends about 1/2 of a page in his 2012 handbook justifying Cretolamna. Glikman used Cretalamna in his original 1958 article but then used Cretolamna in all of his subsequent papers. With the current state of uncertainty with a number of very similar genus we are debating how many fairies can dance on the head of a pin.

Marco Sr.

[cowsharks]

Thanks guys for the interesting ideas, information, theories, etc. I had sort of forgotten how much uncertainty there was with proper identification of some of these teeth; I last recall the interesting topic regarding differences between juvenile Otodus vs. Cretolamna.

This particular tooth only has foramen and no nutrient groove. The root lobes, the distinct U-shape notch, the shape of the crown, the cusps, all evoke Cretalamna to me, or least resemble Cretalamna more than the other species mentioned.

My guess is that many of the sites that produce vertebrate fossils probably hold a few species that perhaps aren't expected to be represented there because of the geologic time scale etc. I have experienced this firsthand with at least three locations in MD; I have personally found shark tooth specimens at locations where the teeth had never been previously reported (at least to my knowledge). For example, I have a Nebrius nurse shark tooth that I found in-situ in in a Miocene layer at Calvert Cliffs. It didn't make sense, but I couldn't make it fit into some other tooth type that did make more sense. I wonder if when this happens, we try to make a tooth "fit" a certain type/species because it makes more sense rather than accepting it as an unexpected anomaly.

I think for now my friend is satisfied that his tooth is likely a Cretalamna from a common site in Alabama. Other folks probably have these in their collection, but have them labeled as one of the other species. Perhaps with more research a more definitive answer will be obtained.

Daryl.

[non-remanié]

Good discussion here. I agree completely Marco. Waters get muddy quickly dealing with fossil sharks teeth, especially when it comes to these quite similar species and genera. I think what you really need to figure this out is faunal analysis with a large sample size. Then you can begin to see patterns and slight differences. And hopefully the fauna is from one specific time period and does not contain a mixed age reworked assemblage. With a large faunal analysis and a reliable date for the fossil bearing formation or layer, then you can compare to other similar aged faunas and hopefully make some better conclusions. Sometimes there's just no easy and clean answer.

The experts can't even agree on the spelling of Cretolamna/Cretalamna. Cappetta spends about 1/2 of a page in his 2012 handbook justifying Cretolamna. Glikman used Cretalamna in his original 1958 article but then used Cretolamna in all of his subsequent papers. With the current state of uncertainty with a number of very similar genus we are debating how many fairies can dance on the head of a pin.

Marco Sr.

[Harry Pristis]

There is an explanation of the "Cretalamna" vs "Cretolamna" spelling discrepancy at ELASMO.COM. You'll have to navigate the tool-bars -->GENERA -->PALEOGENE -->LAMNIFORMES -->CRETALAMNA (scroll to the bottom "notes.")

[siteseer]

Marco Sr.,

I have struggled with teeth like these for years. Unfortunately, I have never been at a site where I could collect my own so I have bought and traded for specimens whenever I could. I'm not sure twiggsensis and koerti are separate species but that is David Ward's opinion. He has seen a large number of these teeth, and as non-remanie noted, that is the key. It would be great to see proposed dentitions drawn from a pool of specimens from where they are common as reported in Table 1 of Underwood et al (2011: p. 53), a nice Middle Eocene reference to have, by the way.

From my own collection I have noticed that the general tooth form appears in the Middle Eocene, especially from South Carolina and Hahotoe, Togo. The teeth have a weak nutritive groove. I have some from the Late Eocene (the Ocala Limestone of Florida and Dakhla, Western Sahara) but those teeth may or may not have even a nutritive pore present.

The apparent reduction of the nutritive groove to just a pore indicates that the ancestor of koerti had a more distinct groove and therefore was a sand shark (= sand tiger) or close relative and Brachycarcharias lerichei seems to be a good fit. The anteriors of koerti sometimes have rather broad-based lateral cusplets but they can also have more hook-like ones like a sand tiger (unless I have confused an actual lerichei tooth)..

Furthermore, as you noted, the extra pair of lateral cusplets offers a possible clue. If the tooth were Cretalamna, it would not have the extra cusplet. One could say that it is an atavism but then Cretalamna is not otherwise known from the Middle-Late Eocene. The odds would be astronomical for a one-in-a-million tooth to also bear a tooth character not seen in Paleocene-Ypresian forms but present in its own ancestor/ancient relative. It's more likely that koerti descended directly from a species that had two pairs of lateral cusplets like B. lerichei.

I have a tooth from Harleyville much like the tooth in question (only slightly wider and about as high). The root is rather corroded so I can't tell if it ever had the extra pair of cusplets. For years I wondered it it was a late-surviving Cretalamna but now I think it is a koerti/twiggsensis upper lateral. Nature doesn't seek to be easily categorized.

Jess

Daryl

I was originally thinking Brachycarcharias lerichei like Don pointed out from the Point A Dam site because of the similarity to teeth from "Muddy Creek". However I can also see the similarity to C. twiggsensis and S. koerti that Eric pointed out. Other similar specimens and more pictures would definitely help. Plus if you could take another picture of this specimen. I can't tell if the specimen you posted has a shallow nutrient grove or not from the picture. That would be an important feature. I just don't remember seeing the additional reduced side cusplet like this specimen has on any of my Cretolamna from Liverpool Point or Muddy Creek. I will check them. However the Brachycarcharias from those sites do have the additional reduced side cusplet on some file positions.

Marco Sr.

[Sélacien34]

I'm personally not convinced with C. koerti / twiggsensis or B. lerichei, maybe i'm wrong but i have a problem with the shape of the quadrangular root with well defined lobes, U shaped notch at the base of the root, lingual protuberance, with foramens, with wide and high triangular cusplets and a thick crown which is less triangular than in koerti / twiggsensis, there is a broad base then the edges are thinner on the middle.. In this tooth, the lateral cusplets are split but not separated either. We are talking about a tooth whose we only see the lingual face. Without coming in the details of the different diagnosis I see more proximity with Cretalamna/Otodus, maybe i'm wrong, and i think that it's an upper lateroposterior.



On the top B. lerichei, beneath C. koerti and 1 twiggsensis, maybe the same specie, then Cretalamna appendiculata from Morroco and NJ (one of them have visible secondary cusplets and another just one more) and the last ones O. obliquus. Just to recall some species of Cretalamna like borealis or hattini can show lateral cusps split for the lateroposterior teeth, common in Otodus at the Eocene age.

Edited July 9, 2014 by Sélacien34

[MarcoSr]

Good discussion here. I agree completely Marco. Waters get muddy quickly dealing with fossil sharks teeth, especially when it comes to these quite similar species and genera. I think what you really need to figure this out is faunal analysis with a large sample size. Then you can begin to see patterns and slight differences. And hopefully the fauna is from one specific time period and does not contain a mixed age reworked assemblage. With a large faunal analysis and a reliable date for the fossil bearing formation or layer, then you can compare to other similar aged faunas and hopefully make some better conclusions. Sometimes there's just no easy and clean answer.

Steve

I definitely agree that a larger sample size with different file positions is needed to help resolve the identification. Can't do it with a single tooth. One of the reasons that we have a lot of the issues that we do with shark tooth identification is because the genus/species describers used small sample sizes and/or a limited number of paratypes in their descriptive papers which left too much ambiguity.

Marco Sr.

[MarcoSr]

Marco Sr.,

I have struggled with teeth like these for years. Unfortunately, I have never been at a site where I could collect my own so I have bought and traded for specimens whenever I could. I'm not sure twiggsensis and koerti are separate species but that is David Ward's opinion. He has seen a large number of these teeth, and as non-remanie noted, that is the key. It would be great to see proposed dentitions drawn from a pool of specimens from where they are common as reported in Table 1 of Underwood et al (2011: p. 53), a nice Middle Eocene reference to have, by the way.

From my own collection I have noticed that the general tooth form appears in the Middle Eocene, especially from South Carolina and Hahotoe, Togo. The teeth have a weak nutritive groove. I have some from the Late Eocene (the Ocala Limestone of Florida and Dakhla, Western Sahara) but those teeth may or may not have even a nutritive pore present.

The apparent reduction of the nutritive groove to just a pore indicates that the ancestor of koerti had a more distinct groove and therefore was a sand shark (= sand tiger) or close relative and Brachycarcharias lerichei seems to be a good fit. The anteriors of koerti sometimes have rather broad-based lateral cusplets but they can also have more hook-like ones like a sand tiger (unless I have confused an actual lerichei tooth)..

Furthermore, as you noted, the extra pair of lateral cusplets offers a possible clue. If the tooth were Cretalamna, it would not have the extra cusplet. One could say that it is an atavism but then Cretalamna is not otherwise known from the Middle-Late Eocene. The odds would be astronomical for a one-in-a-million tooth to also bear a tooth character not seen in Paleocene-Ypresian forms but present in its own ancestor/ancient relative. It's more likely that koerti descended directly from a species that had two pairs of lateral cusplets like B. lerichei.

I have a tooth from Harleyville much like the tooth in question (only slightly wider and about as high). The root is rather corroded so I can't tell if it ever had the extra pair of cusplets. For years I wondered it it was a late-surviving Cretalamna but now I think it is a koerti/twiggsensis upper lateral. Nature doesn't seek to be easily categorized.

Jess

Jess

I have a decent sample size of what experts call Brachycarcharias lerichei from the Paleocene of MD and a very large number (several thousand) from the Eocene of MD, all that I collected. I also have a small number of twiggsensis/koerti. In addition to your observation on the nutrient grove I see the teeth getting somewhat larger and definitely more robust (roots, cusp and cusplets) from the Paleocene to the Eocene. I can see why, as Eric pointed out, Underwood, Ward and others in "Shark and ray faunas in the Middle and Late Eocene of the Fayum Area, Egypt" (2010) place both koerti and twiggsensis under Brachycarcharias. Over the years I have not been able to determine what amount of evolution of tooth morphology, in what appears to be a shark chronological lineage. justifies a new species and/or genus name.

Marco Sr.

[MarcoSr]

I'm personally not convinced with C. koerti / twiggsensis or B. lerichei, maybe i'm wrong but i have a problem with the shape of the quadrangular root with well defined lobes, U shaped notch at the base of the root, lingual protuberance, with foramens, with wide and high triangular cusplets and a thick crown which is less triangular than in koerti / twiggsensis, there is a broad base then the edges are thinner on the middle.. In this tooth, the lateral cusplets are split but not separated either. We are talking about a tooth whose we only see the lingual face. Without coming in the details of the different diagnosis I see more proximity with Cretalamna/Otodus, maybe i'm wrong, and i think that it's an upper lateroposterior.

1.jpg1- otodus obliquus.PNGCret.PNG

On the top B. lerichei, beneath C. koerti and 1 twiggsensis, maybe the same specie, then Cretalamna appendiculata from Morroco and NJ (one of them have visible secondary cusplets and another just one more) and the last ones O. obliquus. Just to recall some species of Cretalamna like borealis or hattini can show lateral cusps split for the lateroposterior teeth, common in Otodus at the Eocene age.

You make a good argument for Cretolamna based upon features of the specimen. However, I still have an issue with the reduced secondary cusplet even though a tooth is shown in the artificial tooth set of Cretolamna appendiculata from Bruce Welton that you provided with the reduced secondary cusplet. That tooth set is from the Albian, Cretaceous period. If it was an associated tooth set than I would believe the tooth with the reduced secondary cusplet shown was from Cretolamna appendiculata. Being an artificial set I'm not 100% convinced. Siverson has named several new genus that occur in the Cretaceous of the US including Cardabiodon which can have an additional pair of very reduced cusplets on some lateral teeth. I also base a lot of my observations on teeth that I have personally collected. I have hundreds of Cretolamna (which experts identify as appendiculata) specimens from the Paleocene and Eocene of the US and none have the reduced secondary cusplets. Shimada (2007) published a partial skeleton with about 120 associated teeth representing the most complete dentition of appendiculata discovered to date. Unfortunately I don't have access to that publication. Do you? If it shows appendiculata teeth with a reduced secondary cusplet than I would be a believer. I still think a much larger sample of teeth from the same site as this specimen is needed for a more accurate id.

Marco Sr.

[Sélacien34]

I do not argue that this tooth belongs to the specie Cretalamna appendiculata, as you say deservedly this specie normally has only 2 lateral cusps, unless an unusual atavism or genetic error. And the upper-middle Eocene age, it's a little late for C. appendiculata unless a rework. I have 2 teeth, one from Morocco and one from New Jersey who have a small budding secondary cusps but I draw absolutly no conclusion with that. I have been looking for the publication of Shimada, unfortunatly, i don't have it.

The only thing that seems apparent to me is that the general characters of the tooth are closer to the Otodontidae than the Odontaspididae.

Edited July 9, 2014 by Sélacien34

[MarcoSr]

I do not argue that this tooth belongs to the specie Cretalamna appendiculata, as you say deservedly this specie normally has only 2 lateral cusps, unless an unusual atavism or genetic error. And the upper-middle Eocene age, it's a little late for C. appendiculata unless a rework. I have 2 teeth, one from Morocco and one from New Jersey who have a small budding secondary cusps but I draw absolutly no conclusion with that. I have been looking for the publication of Shimada, unfortunatly, i don't have it.

The only thing that seems apparent to me is that the general characters of the tooth are closer to the Otodontidae than the Odontaspididae.

I want to thank Don for e-mailing to me the Shimida (2007) paper. When I originally looked at the photos of the C. appendiculata teeth in the printed copy of the paper that I made from the electronic version I could not see any reduced secondary cusplets on the teeth and the photos of the individual teeth from the different file positions were a pretty decent size. However there was one sentence in the text which caught my attention: " Each lateral cusplet in distally located lateral teeth may bear a minute additional lateral cusplets laterally". Going back to the paper copy I still couldn't really see them. So I went back to the electronic copy, increased the size to 400%, and there they were. They really were minute. Most of these secondary cusplets in the teeth shown looked pretty nondescript like your two teeth with small budding secondary cusplets. However, on several teeth these secondary cusplets were very pointed and looked more like an Odontaspidae secondary cusplet. I am going to look back again at all of my C. appendiculata cusplets under magnification. Now I really would like to see more specimens from this site as I believe that they could be in the C. appendiculata lineage based upon the features of the posted tooth.

Marco Sr.